Method for processing textured yarn



Jan. 21, 1969 v DUDZlK ET AL 3,422,617

METHOD FOR PROCESSING TEXTURED YARN Filed Aug. 31, 1966 Sheet of 2 INVENTORS F- l G I CHESTER J. DUDZIK DANIEL J. FISHER JR.

BY GUY E. P R NS W;7/w

ATTORN EYS Jan.21,1969 ,J UDz.K ETAL' 3,422,617

METHOD FOR PROCESSING TEXTURED YARN Sheet g of2 Filed Aug. 51, 1966 l NVENTORS CHESTER J. DUDZIK DANIEL J. FISHER JR. GUY E. PERKINS ATTORNE S United States Patent Claims ABSTRACT OF THE DISCLOSURE A thermoplastic textile yarn such as nylon, Dacron and the like is permanently crimped by the false twist method, and the stretch and recovery properties of the crimped yarn are prevented from decaying upon subsequent exposure to heat, such as may occur during a dyeing operation, to an extent which would otherwise occur by winding up the crimped yarn at very high overfeeds. The very minimum overfeed is about 200% and the preferred overfeeds with certain yarns may be as much as 900%. Special provisions are made to eliminate air currents and static electricity in the winding zone so that the yarn may be managed at the extremely low tensions which accompany the very high overfeeds. Special provisions are also made for forming a uniform package of the yarn being delivered at extremely low tensions by scattering along the length of the package the point at which the traverse of the yarn is reversed.

The invention herein disclosed relates to methods and apparatus for processing textured yarn, that is, yarn made from thermoplastic fibers or other fibers capable of retaining a structural deformation imparted to them in connection with a thermal treatment and which yarn has been subjected to such a structural deformation tending materially to reduce the length dimension of the yarn by imparting a crimped or coiled configuration to it.

One such deforming process involves twisting the filaments of a multi-filament yarn about each other, thermally setting this twist into the yarn and then untwisting it. Such a process and the apparatus for performing it are disclosed in the Dudzik et al. patent, US. 3,152,436. The memory of the deformation imparted to the filaments by the twisting operation is permanent to their structure, so that when the treated yarn is in its relaxed state it assumes a crimped or coiled, i.e., textured, form. When an external force (smaller in magnitude than one which would strain the yarn beyond its elastic limit) is applied to the yarn in the direction of its axis so that the yarn is pulled out to its full length, these permanent deformations produce stresses in the yarn which cause it to return to its former length once the external force is removed. Yarns in which these stresses remain substantially undiminished after many cycles of stretching are sometimes called stretch yarn. Such yarns have become familiar to the consuming public due to their use in stretch fabrics and ultimately in such garments as ski pants, leotards and foundation garments and also more recently in stretch stockings and socks.

One problem that is encountered in the further processing of such textured yarns involving heating them while in the stretched condition is that the stresses urging the fibers to return to their crimped condition tend to decay or relax, so that the yarn loses some of its recovering power or bounce. This phenomenon occurs, for instance, during yarn dyeing. In order to avoid the problem, yarns of this type are frequently rewound into a skein or muff before being dyed. In such a package the yarn is in a substantially unstressed state, so that the application of 3,422,617 Patented Jan. 21, 1969 ICC heat thereto will not cause any appreciable alteration of the structure which creates the stresses urging the return of the yarn from its stretched condition. However, this expedient entails considerable additional yarn-handling, inasmuch as it is necessary to wind the yarn on a first core as it is taken up from the texturing machine, rewind the yarn into a skein or muff for dyeing, and then once more to rewind the yarn from the muff or skein onto another core for further handling. Obviously, these steps are timeconsuming and costly.

One object of the instant invention is to provide a meth od for producing textured yarn in a form which will resist the deformation-decaying effects of subsequent heating of the yarn.

Another object of the invention is to provide a process and apparatus for winding textured yarn on a package in such a fashion that it may retain its bounce and dimension-recovering power during subsequent processing and use.

Still another object of the invention is to provide an apparatus and method for producing a pack-age of stretch yarn which may be processed at elevated temperatures without the need for prior rewinding or re-packaging.

An additional object of the invention is to provide a method and apparatus for winding a self-supporting package of textured yarn in which said yarn is under substantially relaxed conditions in the pack-age.

The manner in which these and other objects of the instant invention are achieved will be apparent to those skilled in this art from a consideration of this specification, especially when taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is a schematic front elevation of a portion of a yarn texturing machine of the type generally disclosed in the said Dudzik et al. patent modified in accordance with the instant invention;

FIGURE 2 is a schematic cross-sectional representation of the same machine, the cross-section taken as indicated by line 2-2 of FIGURE 1;

FIGURE 3 is a schematic front elevation of a portion of a similar machine adapted to the practice of an alternative embodiment of the invention; and

FIGURE 4 is a schematic cross-sectional representation of the machine shown in FIGURE 2, the cross-section taken as indicated by line 4-4 on FIGURE 2.

According to one embodiment of the instant invention, the textured yarn is wound onto a self-supporting package in the substantially relaxed -or untensioned state. This may be accomplished by overfeeding the yarncoming from the false twisting device onto the take-up roll, i.e., winding the yarn up more slowly into the package than it is being fed from the false twister and thus winding it under virtually zero tension, so that the yarn is wound in its relaxed, unstressed condition. Processing steps, such as dyeing, which involve elevated tempera tures will not substantially reduce or decay the stretch qualities of yarn in this condition.

An example of an apparatus on which the instant invention may be practiced is shown in FIGURES l and 2. Supply packages 10, mounted at the base of each position of the machine, each feed an end of yarn to be textured, as for instance a thermoplastic yarn such as nylon, polyester, polyolefin or the like, to the machine.

Each end is passed through a pigtail guide 11, over guide rod 12 to positively driven first feed roll 13. The yarn is held in a non-slip relationship with respect to the surface of roll 13 by the action of associated pinch roll 13a. From here the yarn is passed upwardly, through one of the channels 15 provided at each position in the face of heater 14, to a false twisting device such as spindle 16 shown mounted on crank arm 17 for rotation into and out of frictional contact with drive belt 18 driven by pulley 19. Next the yarn is passed through the second feed roll mechanism 20 to take-up roll mechanism 24 where it is wound on package 27.

Due to the action of the false twisting device 18, the

conduct away the static electrical charges which inevitably build up when the yarn is being wound. A preferred type of static eliminator is one which creates a field of ionized air around the yarn, thus tending to neutralize the charge thereon. Alternatively, static elimination may be accomyarn is in a twisted condition in that segment of its path 5 plished by arranging contact of the yarn with materials between lower feed roll 13 and the false twist spindle 18 which serve to diminish or eliminate the charge of static and in untwisted condition between the spindle 18 and electricity and/or to prevent its subsequent build-up. second feed roll mechanism 20. Inasmuch as the yarn is Deployment of a belt shield 18a between the belt 18 heated above its softening temperature and then cooled which drives the false twist spindles 16 and the yarn being below it again, all While it is in its twisted condition, the overfed to wind-up means 24a is another expedient within deformations imparted to the thermoplastic yarn are more the scope of this invention. The high velocity at which or less permanent in the yarn. belt 18 travels has been found to create considerable wind- The second feed roll means 20 cooperate with the age, the deflection of which by the belt shield greatly intake-up roll means 24 to overfeed this freshly textured creases the manageability of the virtually untensioned yarn onto the package, thus minimizing the decay in crimp yarn. in the yarn which would otherwise tend to occur during In winding textured yarn onto a package the problem subsequent processing of the yarn package. of high end formation has been encountered. As has Second feed roll means may comprise a pair of yarn been explained, the yarn is guided onto the package by advancing rolls 21 and 22 positively driven at a controlled 20 traversing yarn guide 26. This yarn guide is reciprocated peripheral speed ratio to that of the first feed roll means through a constant amplitude as the yarn package is and to that of the take-up roll means. Pinch roll 23 is rotated to distribute the yarn thereon. Inasmuch as the spring-biased into rolling engagement with the larger linear velocity of this yarn guide reaches its minimum (22) of the pair of yarn advancing rolls of second feed (zero) at the extremities of its reciprocating path, more roll means 20, so that the yarn is held securely in a non- 25 yarn tends to be deposited at the extremities of the packslip relationship with said rolls. age than in the center causing the package to have high The take-up mechanism 24 for alternate positions may nd A a Solution to this problem it has been proconveniently be positioned, respectively, above and below Posed to reciprocate the Y guide through a scatter the lateral space requirements therefore, as indicated by ing device which serves to scatter the mid-points of Suereference numerals 24 and 24 i th d i E h cessive reciprocations and thereby distribute the ends of take-up mechanism 24 comprises a guide rod 25, a trathese reciprocations axially on the package. One such versing yarn guide 26 for distributing the yarn on package scattering device, useful in the practice of the instant 27 which is driven by drive-roll 28 in peripheral contact invention, is disclosed in Patent aPPiicatiOh therewith. Imparting to the package the rotational mofiled 1966, y Daniel sh r. T tion necessary for winding by means of a peripherally Y guide 26 is mounted on Tod and feeiproeated y contacting roller assures that the yarn will be Wound at a it y means n t sh wn. The scattering device (also not constant linear velocity regardless of the diameter of the shown) is Conveniently interposed between the means mass of yarn already wound on the package. Inasmuch ciprocating the said rod and the rod itself in the manner as the overfeed ratio is the ratio of the linear velocity of indicated in the said Fisher et pp the yarn passing through the feed roll mechanism to that Thehfeticaliy, the maximum overfeed With Which Yarns of the yarn being wound on the package, it is important Could be wound on the package would be that which would that wind-up proceed at a constant velocity if overfeed correspond to Winding the teXthIed Y at its totally is to be carefully cont-rolled. To further assure a controlled iaXed Thus, for example, a Particular textured rate of overfeed, shaft 28s, which drives roll 28, is rotated Y Which has a feiaXed length of for every 100 at a definite ratio to the rotational speed of shaft 20s of initial (PFeteXthTed) length is Capable of being which propels the second feed roll means 20. This is stretched to accomplished by belts 29 connecting pulleys 20p with 0 5 pulleys 28p. Selection of the relative diameters of pulleys TX 100%=1076% 20p and 28p thus determines the package overfeed ratio. i

In the course of overfeeding the yarn to the package of relaxed length and could be Wound at a 1076% in accordance with the instant invention problems of yarn rfi managgment are encountered which may traced to the e maximum practical overfeed rate achievable for f t h the very lively textured yam traverses the f y given y rn is much greater when the means of the instant lnventlon are em loyed than was osslble heretotance between the second feed roll means and the wind-up p p means at a g velocity under l] no tension Me fore. Nevertheless, the maximum practical overfeed rate t th M b y is less than the theoretical overfeed rate as computed ures o overcome 686 P ems been devised Whlch above. These values are compared for a number of texare within the scope of this lnventlon. tured yarns in Table I below.

TABLE I (A) (B) (C) (D) (E) Maximum theoretical Equivalent relaxed 1 Equivalent relaxed Yarn conlpogition, denier/No. Total relaxed length,

overfeed, percent len th at max. racl t atm r t 1 Maximum practical g p g D actlca tical overfeed cm. overfeed as a percent aments cm. er 100 cm. Hut 1 10 y y p length la 0 0(2) (A) X10072) overfeed as measured 10,000 of totally relaxed length D A IOU-HG) (TX1O0% Nylon 66 30/10 7. O 1, 330

Nylon 66 70/13 8.2 120 i 'ii 2% Nylon 66 70/17 10. 0 900 600 14' 3 43' 0 Nylon 66 70/34 l4. 5 590 421 19 2 44 8 Nylon 66 100 34- 10.5 852 57s 1418 41' 0 The operation of a static elimination device 30 in the region proximate to the yarn adjacent to the nip of second feed roll 22 and pinch roll 23 improves the handling characteristics of the yarn. The static elimination device may be of any desirable design which serves to neutralize or to The maximum practical overfeed rate has been discovered to be that which deposits yarn on the package at such a rate that it is extended to a length approximately forty percent (40%) greater than its totally relaxed length. In the case of the sample calculation offered above,

this would amount to a minimum practical equivalent relaxed length of yarn in the package of for every 100 cm. of initial length, or a maximum overfeed rate of Thus, to determine the maximum overfeed with which any particular textured yarn may be wound on the package in accordance with the instant invention it is only necessary to determine the totally relaxed length of a standard initial length of the yarn, and set the overfeed mechanism to lay the yarn on the package at an equivalent length at least approximately 40% greater than that value.

Overfeed rates lower than this may of course be used and will nevertheless produce yarns which at least partially enjoy the advantages conferred by the instant invention. As a practical matter, however, an overfeed rate which lays the yarn on the package at an equivalent length of much over 50% of its initial (pre-texturing length), i.e., an overfeed rate of substantially under 100%, may not suffice to confer the advantages of the invention upon a particular yarn.

To certain yarns, namely those which have a particularly troublesome tendency toward entanglement when being overfed to the package in accordance with the embodiment of the invention disclosed above in conjunction with the apparatus of FIGS. 1 and 2, it has been found desirable to apply the principle of the invention in accordance with other embodiments thereof.

One such embodiment is slightly to pretwist the yarn before subjecting it to the false twist and overfeed windup operation. Thus, for instance, a yarn containing 3 turns per inch of S twist may be supplied to the process described above, in which the false twisting is in a Z direction. These relatively few turns per inch of twist serve to keep the yarn in integral form during overfeeding, thus avoiding yarn entanglement and fouling.

Yet another embodiment of the inventionrnay be employed to great advantage with yarns which are particularly troublesome in this regard. This embodiment of the invention may conveniently be practiced in conjunction with apparatus such as that depicted in FIGURES 3 and 4. The yarn supplied to this apparatus, as on package 50 has already been textured and wound in conventional fashion, i.e., without application of the overfeed principles of the instant invention. The yarn may also be one which has been produced by twisting together two or more plies which have been individually textured in conventional fashion.

As may best be seen in FIGURES 3 and 4, bobbins of yarn 50 are suspended from the structure of the machine in any suitable manner. At each station, the yarn Y is drawn from the package 50 by means of a feed roll mechanism comprising a pair of yarn advancing rolls 52 and 53. After passing around the feed roll, the yarn passes downwardly through a groove or channel 55 extending transversely of the insulated face of the heater 54.

After exposure to the heater, the yarn is wound onto package 56 after passing over guide rod 59 and through traversing yarns guide 60 mounted on reciprocable traverse rod 61. Take-up drive roll 57 tangentially engages package 64 to drive it at a constant rate regardless of the diameter of the mass of yarn already built up on the package 56. In a manner similar to that discussed relative to FIGS. 1 and 2, a suitable prime mover rotates the take-up drive roll 57 through conventional gearing, drives a cam to impart periodic reciprocal movement to the yarn guide 60, and drives the feed roll means 52.

Belt 62 passes over pulleys 63 and 64 to synchronize the rotational speed of feed roll mechanism 51 with that of take-up drive roll 57. As in the case of the apparatus of FIGS. 1 and 2, the overfed rate is determined by the relative sizes of pulleys 63 and 64. v

The employment of a scattering device to minimize the problem of high ends, as well as the deployment of static elimination means is as advisable and desirable with this apparatus as with that of FIGS. 1 and 2.

By the process described, the plied yarn is heated to the point necessary to develop its crimp, but not to the point where the crimp relaxes. Then the yarn is packaged at a high rate of overfeed in accordance with the principle of this invention as explained hereinabove, thereby to capture and preserve the high degree of stretchability possessed by the yarn.

The efiicacy of the instant invention will now be illustrated by a number of working examples. In these examples the extent to which the yarns retain their bounce, or their power to return after having been processed at elevated temperatures to the relaxed length which they had after texturing, is measured by a standardized test called the Leesona Stretch Yarn Skein Test. The procedure for this test is to wind the yarn to be tested into a standard skein, measure its length L apply a weight of 20 grams to one end thereof and submerge the weighted skein in water at 180 F.- -5 for ten minutes. Thereupon, the skein is removed from the water and allowed to hang for three to five minutes with the weight still applied thereto, and its length L is again measured. The shrinkage value is recorded as:

EXAMPLE I A singles end of 70 denier, 34 filament raw Nylon 66 yarn is processed on the apparatus depicted in FIGS. 1 and 2. The first feed roll 13 is operated at a peripheral speed 3% above that of the second feed roll means 20, which in turn is operated at a peripheral speed above that of the package. i.e., a package overfeed of 208%. The heater is maintained at a temperature of 440 F. The false twist spindle is rotated at a speed of 240,000 r.p.m., imparting turns per inch to the advancing yarn. The package, as wound, is thereupon dyed in a conventional manner at a temperature of ZOO-210 F. When dyed yarn is then subjected to the Leesona Stretch Yarn Skein Test it is found to have a skein shrinkage of 47.5%.

EXAMPLE II A sample of the yarn of Example 1, taken before the dyeing operation is subjected to the Leesona Stretch Yarn Skein Test. The yarn so processed exhibits a skein shrinkage of 53.6%.

EXAMPLE III This example serves as a control. A singles end of the same 70 denier 34 filament raw Nylon 66 yarn as in Examples I and II is processed on the apparatus of FIGS. 1 and 2 at a bottom overfeed of plus 3% and a package overfee-d of plus 50%. Heater temperature is 440 F. and the false twist spindle rotates at a speed of 240,000 r.p.m., imparitng 80 turns per inch to the travelling yarn. The yarn is dyed as in Example I. The yarn so processed has a skein shrinkage of 39.4%.

In addition to the specific embodiments of the instant invention described herein, others will be apparent to those with skill in this art. Such other embodiments are intended to be within the scope of the instant invention as claimed.

What we claim is:

1. A method of reducing the decay in the stretch characteristics due to subsequent exposure to heat of a thermoplastic textile yarn which has been permanently crimped by the false twist method which comprises advancing the crimped yarn at a given rate to a winding zone under tension which prevents the appearance of crimp in the yarn, gathering the advancing yarn in the said Winding zone on a rotating package at a second rate which is less than the said given rate to the extent that crimped yarn gathered on said package has an equivalent length at least 40% greater than its fully relaxed length and is no more than one-third of the length of the yarn prior to said crimping by the false twist method.

2. A method as claimed in claim 1 which includes the steps of eliminating static electricity from the environs of the yarn in said winding zone and shielding said zone from air currents.

3. A method as claimed in claim 2 wherein the yarn being gathered on said rotating package is continuously traversed with respect thereto so that the traverses terminate at various points along the axis of the package.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 1/ 1962 Australia. 12/1957 Great Britain. 12/ 1959 Great Britain. 10/ 1960 Great Britain.

1/ 1961 Great Britain.

FRANK J. COHEN, Primary Examiner.

W. H. SCHROEDER, Assistant Examiner.

US. Cl. X.R. 

